Conventionally, a force-sense-imparting operation device (hereinafter, also simply referred to as an “operation device”) described in Patent Literature 1 is known.
As shown in FIGS. 18 and 19, an operation device 100 includes a rotating section 101 supported so as to be rotatable around a center point c, an operation lever 103 for rotationally operating the rotating section 101, and a stationary section 104 that encircles a periphery of the rotating section 101 in a state where the rotating section 101 is rotatable.
The rotating section 101 has a magnetic pole section 102 that extends toward the stationary section 104 from the center point c. The magnetic pole section 102 is formed by a permanent magnet. The stationary section 104 has a plurality of stators 105 which extend toward the center point c and which are aligned at intervals in a rotational direction of the rotating section 101 and an excitation coil 106 formed by distributed winding of conducting wires around the plurality of stators 105.
In the operation device 100, when an excitation current supplied to the excitation coil 106 is controlled, each stator 105 constructs a magnetic pole on the side of the stationary section 104. As a result, a magnetic attraction force acts on the magnetic pole (permanent magnet) 102 of the rotating section 101. A torque around the center point c created at the rotating section 101 by the magnetic attraction force is used as a force sense that is perceived by an operator or the like when operating the operation lever 103.
However, with the operation device 100 described above, an expensive magnet such as a neodymium magnet is used as the permanent magnet 102 in order to obtain a large force sense (torque). This results in significantly high cost. In addition, with the operation device 100 described above, demagnetization of the permanent magnet 102 may occur when an overcurrent is supplied to the excitation coil 106 at short-time rating or the like to form a strong magnetic field. Furthermore, when the excitation coil 106 is heated by an overcurrent flowing through the excitation coil 106 or when the operation device 100 is used in a high-temperature atmosphere, the permanent magnet 102 is exposed to high temperature and, consequently, demagnetization or neutralization of the permanent magnet 102 may occur.